Vacuum switch



D. C. PRINCE VACUUM swmca Filed Oct.

Invenbov David C. PYince, W m His 'Atbovneu.

\ PatenteclDec. 26, 19

UNITED David C. Princ STATES 1,941,273 VACUUM SWl'I'CH P e, Swarthmore, Pa., assignor to General Electric Company,

a corporation of New York Application October 29, 1931. Serial No. 571,833

a 6 Claims. 200-87) 10 out with particularity in the claims annexed to invention; Fig. 2 is a similar erally indicatedat I mounted, as will be hereinthe lead conductors for the and 6, which are arranged to be bridged by the] 7' in the closed circuit position, are mounted on flexible lead-con- 3o ductors 7 and 8 respectively and are provided with so'that when the contact 7' is biased into and out For the purpose of efiecting relative movement 40 of the contacts, the contact 7' is provided with an operating rod 9 extending laterally into extenthe ends and exteriorly of extensions 10 and 11 tensions 10 and 11 respectively. The relation being not only as positioning and guiding means for the short-circuited rings, but also for receiving the middle leg of the corresponding E-shaped v magnet so that the short-circuited coil is, prior of the magnet.

In order to absorb the force of the circuit opening movement, which is generally eflected quickly and with minimum delay, the reentrant p0r-' contacts 5 and 6. By way of example, thereare illustrated conrol circuits for opemng switch 22 and the coil- 21 through a suitgo I surfaces in the event that small particles are frozen or stuck together due to the welding action of heavy currents. Furthermore, the sudden inductive re pulsion' of the short-circuited ring 14 exerts a percussive-like force tendmg to separate the con- The construction shown in Fig.- 1-is preferably I such that all the parts within the switch enmuch more easily velope may be freed of occluded gases and other objectionable impurities without difficulty. For example, the short-circuited rings 14 and 15, as well as the supporting means therefor and the operating rod 9, are preferably of material which may be effectively degassed as by heating with induced currents. The short-circuited rings may be of copper or nickel, which for example are degassed than iron, or they may be composed of a refractory metal as tungsten or molybdenum, although in the latter instance the materials have more resistance to induced currents. The vacuum switch envelope and enclosed elements are thoroughly freed of occluded gases, as by well-known baking-out processes, so that, once attained, a high vacuum may be maintained within the envelope notwithstanding heating of the contacts and other parts by the current. The degree of evacuation is preferably as high as can be practically attained and may be of the order of 1/100 of a micron.

It will be apparent that, if desired, one of the' actuating magnets may be dispensed with and suitable biasing means, as a spring for example, substituted so as continually to bias the movable contact in one direction. In this arrangement the single magnet overcomes the bias of the spring or other means in operating the movable contact.

.In the form of my invention shown in Fig. 2, the switch envelope 2 is generally similar to that shown in Fig. l with the exception that but one of the contacts 'need be flexibly mounted within the envelope. In the present arrangement, a pair of contacts are employed including a fixed contact 26, suitably sealed through the extension 3 in the envelope, coacting with a movable contact 2'7. The contact 27 is mounted for limited pivotal movement, as by the resilient strip 28 sealed through the extension 4, engagement of the curved or spherical surfaces of the contacts 26 and 2'7 resulting in a combined rolling and wiping action as in the preceding instance. The operating means for the contact 27 may also comprise a pair of magnets 12 and 13 energized by the closing and opening coils 20 and 21 respectively. The short-circuited rings 14 and 15 are suitably connected to an operating rod 29 which is provided with a loop or ring 30 within which a supporting portion 2'7 of the contact 2'7 is positioned. As shown, there is provided a lost motion connection between the operating rod 29 and the contact 2'7 arranged so that initial movement and momentum of the corresponding short-circuited ring are attained before engagement with the movable contact 2'1. This results in a percussive or hammer-like blow being delivered to the movable contact so that the contact surfaces may be readily separated if any freezing should occur. Furthermore, due to the resilient supporting strip 28 the contact surfaces are subjected to a prying action due to the lever action of the movable contact and are readily separated. The curvature of the resilient strip 28, due to the bias of the operating rod 29, also results in a combined rolling and wiping action of the contact surfaces positively freeing the same.

The operation of the contact actuating rod 29 is substantially the same as described in connection with Fig. 1, the envelope 2 being suitably provided, as at the reentrant portions 16 and 1'7, with suitable buffer structure 18. Energization of the closing coil 20 causes repulsion of the ring 14 with the result that the contact portion 27 is engaged by the loop 30 pivoting the contact 2'7 about its resilient support into engagement with the coacting contact 26. As above indicated, the resilient nature of the contact support 28 permits continued movement of the actuating rod 29 to a certain extent after actual engagement of the coacting contact faces. This continued movement, as in the case of Fig. 1 produces a combined rolling and wiping, action of the contact faces. Opening of the switch is effected by energization of the opening coil 21 in any suitable manner causing repulsion of the ring 15 and corresponding movement of the actuating rod 29. Due to the lost motion connection at the loop 30, the contact support 2'7 is sharply struck after initial movement of the actuating rod, tending to free the contact surfaces. If the sticking persists, however, continued movement of the rod 29 causes flexing of the support 28 and consequent rotation of the contact 27 about its own contact face. Due to the strong lever action any frozen particles are readily broken by the aforesaid prying action.

In Fig. 3 there is illustrated a vacuum switch generally similar in so far as the contact structure is concerned to that illustrated in Fig. 2. In this case the switch envelope 2 is provided with an extension 31 housing an actuating electromagnet 32 energized as by leads 33 sealed through the wall of the envelope. The magnet 32, however, may be positioned exteriorly of the glass envelope 2 for the purpose of simplifying the degassing operation ofthe switch. Coacting with the magnet 32 is an armature 34 resiliently mounted, as by a spring 35, with respect to the switch envelope wall. The spring 35 as well as the resilient support 28 of the contact 2'7 may be suitably sealed through the wall of the switch envelope as indicated. For the purpose of actuating the contact 27 the armature 34 is provided with a hook or loop member 36 providing a lost motion connection between the armature 34 and the contact 2'7 of the character above described. The closing magnet 32 when energized attracts the armature 34 causing movement of the contact 2'7 by the hook or loop 36 to closed circuit position. This operation may be substantially the same as that described, the resilient support 28 flexing so as to produce a combined rolling and wiping action of the contact surfaces. Opening of the switch is effected by deenergization of the magnet 32. The armature 34, which is normally biased to the position shown in Fig. 3 by its supporting spring 35, flies back and sharply strikes the contact support 2'7" freeing the contacts and causing opening of the circuit. As in the previous instance the momentum of the armature 34 results not only in a percussive blow tending to free the contact surfaces but also in a prying action at the contact surfaces by rotation of the contact 2'7 about its contact face.

It should be understood that my invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. A vacuum switch comprising an evacuated envelope, relatively movable contacts having coacting spherical contact surfaces within said envelope, one of said contacts having a spring mounting, a member having a lost motion 4. A vacuum switch comprising an evacuated envelope, coacting stationary tacts mounted within said envelope, a spring and movable conmember on which the movable contact is mounted, an armature having a lost motion connection with said movable contact, means resiliently tacts being operatively connected through a losthammer-like blow to eifect contact opening movement.

6. A vacuum switch comprising an evacuated envelope, coacting contacts mounted for relative movement within said envelope, means within said envelope operatively connected to said contacts including ing 

